EP1890269A1 - Provision of a function of a security token - Google Patents

Abstract

The initialization process for a physical security token (20) in a host system (10). A virtualization process (34, 36, 38) based on the physical token creates a virtual one (30) in a secure region of the host system. The required initialization data are sent via an encrypted channel (32) from the physical token to the host system, so that the virtual one initializes the function without recourse to the physical one.

Description

The invention relates generally to the field of security tokens, and more particularly to the field of providing a security token function on a host system. For example, a security token in the wording of the present document may be a smart card in various forms or a chip module - e.g. in the form of a USB plug - his. A word-for-word host system in this document is generally any device that uses the security token function.

In mobile telecommunications equipment - e.g. Mobile phones - typically SIM or USIM cards are used as security tokens. These cards are permanently in the telecommunication device and are powered by this during the entire period of operation of the telecommunication device. Especially with compact telecommunication devices, it would be desirable to be able to use the space required by the card elsewhere. Furthermore, it is desirable to keep the power consumption of the telecommunication device as low as possible. Similar problems exist with other portable security systems that use smart cards or other security tokens.

Another application of security tokens is access authorization systems for encrypted media data, e.g. Decoder for pay-TV programs. Such systems often have multiple slots for smart cards of several providers of pay-TV programs. However, each slot is costly, so it would be desirable to be able to provide high user convenience even with only one slot.

Furthermore, security tokens are increasingly being used for two-factor authentication in security-critical applications; the host system in this case is a standard computer or embedded System. Again, there is a need to achieve the highest possible ease of use with the least possible effort.

US 2002/0080190 A1 shows a system for creating and managing "virtual smart cards". A control program reads out the data contained in a physical chip card and stores it, for example, on a hard disk or a CD-ROM. The stored data can be used for backup and quick recovery of smart cards or edited by the control program. The control program may also provide the functions of the smart card for application programs if the smart card has been damaged or lost.

Out WO 03/052565 A1 For example, a computing device is known that includes a physical security token and a protected storage area with a virtual security token. The physical token is used to obtain a credential (credential) for the virtual token.

WO 2004/021715 A2 discloses a method to use a single SIM card simultaneously in a mobile phone and by a personal computer. The SIM card is in the mobile phone. Requests to the SIM card from the computer are sent via a Bluetooth® interface to the mobile phone and answered there by the SIM card. The answer is transmitted to the computer via the Bluetooth interface.

US 2004/0072591 A1 shows an apparatus for checking access to mobile telephone networks, in which a plurality of real SIM cards of different service providers are arranged in a central unit. Mobile testing devices access these SIM cards. In this case, the test devices send authentication requests to the SIM cards and receive the answers generated by the SIM cards.

Out US 2005/0227729 A1 For example, a mobile phone intended for use by multiple users is known. A memory card with personal data such as a telephone book, e-mail data or settings data can be connected to the mobile phone. When a user logs on to the mobile phone, the data is transferred from the memory card to the mobile phone, and when the user logs off, the data is transferred back to the memory card.

It is an object of the invention to provide a technique which provides high security while avoiding problems associated with the use of prior art security tokens. In some embodiments, the invention is intended to help provide devices with particularly low power consumption and / or particularly compact devices and / or particularly cost-effective devices and / or particularly convenient to use devices.

According to the invention, this object is achieved in whole or in part by a method having the features of claim 1 and a host system having the features of claim 12. The dependent claims define optional features of some embodiments of the invention.

The invention is based on the basic idea of carrying out a virtualization process in which, with access to a physical security token, a virtual security token is created in a secure area of the host system. After completing the virtualization process, the virtual security tokens provide at least one physical security token feature. The physical security token is then no longer needed in most embodiments and may be disabled and / or removed, for example.

Through the use of a cryptographically secured communication channel for data transmission and a secured area for creating the virtual security token, the invention provides the technical basis for storing secret data contained in the physical security token, even during transmission to the host system and during use to reliably protect the virtual security token. Therefore, safety-critical functions, e.g. Encryption or decryption functions or authentication functions, are taken over by the virtual security token.

For security reasons, in some embodiments, the virtualization process is executed each time the host system is booted, requiring the physical security token at any one time.

While in many embodiments there is a one-to-one correspondence between the physical and virtual security tokens, embodiments are also provided in which a single virtual security token is generated from multiple physical security tokens or multiple virtual security tokens are generated from a single physical security token.

The host system according to the invention is developed in some embodiments with features that correspond to the features described above and / or the features mentioned in the dependent method claims.

• Fig. 1 ein Blockdiagramm eines Host-Systems und eines Sicherheitstokens in einem Ausführungsbeispiel der Erfindung,
• Fig. 2 eine Darstellung logischer Strukturen in dem in Fig. 1 gezeigten Ausführungsbeispiel, und
• Fig. 3 ein Ablaufdiagramm eines Virtualisierungsvorgangs in einem Anwendungsbeispiel der Erfindung.

Other features, advantages and objects of the invention will be apparent from the following detailed description of exemplary embodiments. In the schematic drawings show:

• 1 is a block diagram of a host system and a security token in an embodiment of the invention;
• FIG. 2 is a diagram of logical structures in the embodiment shown in FIG. 1; and FIG
• 3 is a flowchart of a virtualization process in an application example of the invention.

In the schematic representation of FIG. 1, a processor 12 and a memory 14 with an operating system 16 are shown as components of the host system 10. For example, the host system 10 may include a portable device - e.g. a mobile telecommunications device - or a conventional computer or embedded device - e.g. an access authorization system. It should be understood that the host system 10 may include other components, e.g. a power supply, a keyboard and a display - has, however, which are not shown in Fig. 1 for reasons of clarity.

The host system 10 further includes an interface 18 via which a security token 20 is connected to the host system 10. The security token 20 is for example a chip card or a chip module. The interface 18 is adapted to the security token 20; For example, the interface 18 according to a common standard for smart cards - eg ISO / IEC 7816 or GSM 11.11 - or as a USB interface or as an interface for a memory card - eg an SD, MMC or SMMC card. The security token 20 conventionally includes a processor and memory with operating system and other components; However, these components are not shown in Fig. 1 for the sake of clarity.

The operating system 16 of the host system 10 is a multi-tasking security operating system that allows the host system 10 to execute processes in their own separate areas. These regions are shown in FIG. 2 by the reference numerals 22A, 22B, 22C and are collectively referred to as regions 22x. The operating system 16 partitions the resources of the host system 10 - e.g. Memory space in the memory 14 and processing time of the processor 12 - in the areas 22x, so that the areas 22x are securely isolated from each other and also no unauthorized access from outside to one of the areas 22x is possible. This allows safety-critical data, e.g. cryptographic keys to store and process in the areas 22x.

As shown in FIG. 2, during operation of the host system 10, an operating system kernel 24 provides essential basic functions. Other operating system functions are executed in at least one area reserved for operating system services 26 - here, for example, area 22A. The operating system kernel 24 is in some embodiments a microkernel, such as the microkernel known by the name L4, which is described in the article " Toward Real Microkernels "by Jochen Liedtke, Communications of the ACM, Vol. 39, No. 9,1996, pages 70-77 , is described. Such a microkernel can achieve a particularly secure isolation of operating system processes. However, the invention is not limited to microkernel operating systems.

The area 22B in Fig. 2 is for executing an application program 28 of the host system 10. It should be understood that the host system 10 may include other application programs - in the area 22B or in other areas.

In area 22C, when starting the host system 10 and booting the operating system 16, a virtualization process is performed in which a virtual security token 30 is created. For this, the physical security token 20 is required. In the virtualization process, a cryptographically secured communication channel 32 is established between the physical security token 20 and the process that invokes the virtual security token 30. For example, a mutual authentication may take place during which the security parameters for an encrypted connection - e.g. a symmetric session key - to be agreed. These security parameters are known only to the physical security token 20 as well as the process that creates the virtual security token 30.

Since the cryptographically secure communication channel 32 is neither accessible to other processes in the host system 10 nor to an external attacker, all-even highly confidential-information can be transferred from the physical security token 20 to the virtual security token 30. This allows the virtual security token 30 to take over all the functions of the physical security token 20 during further operation. There is therefore a "complete virtualization of the security token" instead.

After completing the virtualization process, the physical security token 20 is no longer required. It can be switched off and / or removed. Turning off the physical security token 20 reduces power consumption. When the physical security token 20 is removed, the interface 18 and / or the space occupied by the security token 20 may be used for other purposes.

The virtual security token 30 is implemented by a process that runs in region 22C and accesses data also stored in region 22C. The operating system 16 hereby ensures that the area 22C has a fixed, isolated memory and a guaranteed quota of computing time available. The storage protection prevents unauthorized access of other processes to the data of the virtual security token 30, while the quota of computing time ensures the availability of the virtual security token 30 in the host system 10.

When the host system 10 is powered off or shut down, in the present embodiment, the virtual security token 30 is cleared so that the physical security token 20 is needed again at the next boot.

Overall, the system described herein achieves end-to-end security between the physical security token 20 and the host system 10. In other words, data to be kept secret exists only within the physical security token 20 and within the secure area 22C in plain text. As high demands are placed on the security of the operating system 16 and the partitioning of the area 22C, in some embodiments, the host system 10 includes a TPM ( Trusted Platform Module ) to secure the operating system 16 is used. In other embodiments, the role of the TPM is inherited by the physical security token 20 as long as it is attached to the host system 10. However, embodiments are also provided in which no special protection hardware is used in the host system 10.

FIG. 3 shows the virtualization of the physical security token 20 in an example application where the security token 20 is a SIM or USIM card and the host system 10 is a mobile phone. With regard to its design, the security token 20 may be, for example, a SMMC card ( Secure Multi-Media Card ), and accordingly the interface 18 of the host system 10 is designed as an MMC slot. The illustration of Fig. 3 is not limited to the application example just mentioned, but applies to many embodiments of the invention. For example, host system 10 may be a production system or certification system or other system that uses smart cards as physical security tokens.

The virtualization process shown in FIG. 3 is triggered by the powering up and powering up of the host system 10. At this time, the physical security token 20 must be present, that is, in the present example, the SMMC card is plugged into the MMC slot of the mobile phone. In alternative embodiments, alternatively or additionally, other triggering events may be provided for the virtualization process.

The secure communication channel 32 is now set up in a build-up process 34, for which purpose, for example, a challenge-response authentication with key negotiation is carried out. You can do this known cryptographic techniques, such as Secure Messaging or SSL / TLS protocols, may be used.

The required contents - eg keys and data - of the physical security token 20 are now transferred in a transfer process 36 from the physical security token 20 into the secure area 22C of the host system 10. This content is then used in a create operation 38 to create the virtual security token 30 in region 22C. The docking operation 38 may be performed in some embodiments upon completion of the transfer operation 36. In general, however, the transfer process 36 and the application process 38 completely or partially overlap and are executed in parallel or interleaved , as shown in Fig. 3.

After the initialization of the virtual security token 30 in the host system 10, the create operation 38 and thus the entire virtualization process are completed. The behavior of the physical security token 20 is now emulated by the virtual security token 30. All requests during further operation of the host system 10, e.g. come from the application program 28 are directed to the virtual security token 30 and answered by this. The communication takes place according to the same standards as would be relevant for the physical security token 20, e.g. ESTI or ISO / IEC 7816 standards.

The physical security token 20 is no longer needed. It is switched off in step 40, ie disconnected from the power supply of the host system 10. Now, the physical security token 20 can be removed from the interface 18. In the present example, this frees up the MMC slot of the mobile phone. This slot can then be used eg for "normal" MMC memory cards are used. In some embodiments, the operating system 16 of the host system 10 may decide on further uses of the interface 18. For example, it may be provided that only memory cards of a particular system operator are accepted.

In the embodiment just described, a single physical security token 20 has been converted to a single virtual security token 30. However, such a 1: 1 mapping is not mandatory in some embodiments. Rather, embodiments are provided in which a virtual security token is generated from a plurality of physical security tokens, and vice versa.

An example of an application for using multiple physical security tokens 20 is a certification authority, e.g. Issue X.509 certificates. At such a certification authority, the host system 10 may be a signature unit that operates with a "virtual smart card" as a virtual security token 30. In some embodiments, it may be provided that to generate the virtual security token 30, multiple physical security tokens 20 belonging to different users are requested. This measure achieves a particularly high overall security of the certification authority.

Another application example results in a physical security token 20 that combines several functions. For example, a smart card may be configured both as a SIM for mobile communication services and as a decryption card for digital television. Because of the limited data throughput through the interface of the smart card and / or the limited computing power may be the use not possible at the same time. Here, virtualization can provide a remedy if in the host system 10 more computing power for the virtual security token 30 and / or a higher communication bandwidth between the virtual security token 30 and the application programs - eg 28 - is available. In various embodiments, the physical security token 20 may be implemented in a single or multiple virtual security tokens 30.

It is understood that the above description and the drawings are only intended to illustrate the invention with reference to exemplary embodiments. Further modifications - in particular combinations of the features described above - are immediately apparent to the person skilled in the art.

Claims (12)

A method for providing a physical security token function (20) in a host system (10), wherein in a virtualization process (34, 36, 38) accessing the physical security token (20), a virtual security token (30) in a secure area (22C) of the host system (10), thereby transferring data required to provide the function via a cryptographically secured communication channel (32) from the physical security token (20) to the host system (10), such that upon completion of the virtualization operation (34, 36, 38), the virtual security token (30) provides the function without resorting to the physical security token (20). A method according to claim 1, characterized in that the virtualization process (34, 36, 38) is executed at least every time the host system (10) is powered up. A method according to claim 1 or claim 2, characterized in that the physical security token (20) is turned off after completion of the virtualization process (34, 36, 38). Method according to one of claims 1 to 3, characterized in that the physical security token (20) after completion of the virtualization process (34, 36, 38) from the host system (10) is separable. Method according to one of Claims 1 to 4, characterized in that the function provided is a function requiring secret data to be executed in the physical environment Security token (20) are included and in the course of the virtualization process (34, 36, 38) are transmitted to the host system (10). Method according to one of Claims 1 to 5, characterized in that the function provided is a cryptographic function, in particular an encryption or decryption function or an authentication function. Method according to one of Claims 1 to 6, characterized in that the virtualization process (34, 36, 38) comprises a construction process (34) for establishing the secure communication channel (32), a transmission process (36) for transmitting the data required for providing the function and a docking operation (38) for applying the virtual security token (30). Method according to one of claims 1 to 7, characterized in that the physical security token (20) is a chip card or a chip module. Method according to one of claims 1 to 8, characterized in that the physical security token (20) is a SIM or a USIM, and that the host system (10) is a telecommunication device. Method according to one of claims 1 to 9, characterized in that in the virtualization process (34, 36, 38) off a plurality of physical security tokens (20) a single virtual security token (30) is generated. Method according to one of claims 1 to 9, characterized in that in the virtualization process (34, 36, 38) a plurality of virtual security tokens (30) are generated from a single physical security token (20). A host system (10) comprising a processor (12) and a memory (14) adapted to carry out a method according to any one of claims 1 to 11.

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